Tampa 928s

Welcome to my world

Hawkeyes

Rich just called me - my LH tests fine; he installed it in his 928 & took a ride...Doh!!!

John, following your suggestion...
* Confirmed 12v on EZK pin 35.
* Tested continuity between EZK 35 and LH 1 - measured .45 ohm.
* Tested resistance between EZK 35 and chassis - measured 5.5k ohm.

For whatever reason, the EZK must not be sending a signal to actuate fuel pump and injectors. But it DOES signal Ignition Final Stage units to spark. So RPM sensor must be OK, right?

(the 'reference mark sensor' on this car was replaced in January - does reference mark sensor = RPM sensor?)

So is the EZK unit faulty?

What else can I test to find out why EZK is not sending a signal to injectors and fuel pump?

Hawkeyes

John Speake

Your flywheel sensor is OK. People do get confused with ref mark sensor and flywheel sensor, but yours is OK.

If EZK is giving a spark, then unlikely it is the problem.

The EZK sends an rpm signal from pin 13 to pin 1 LH. When the LH receives that signal it will energise the fuel pump. The same signal is also used to time the injector firings.

Connect your multimeter between pin 1 LH and ground, switched to a.c volts. Then crank the engine. You should get a reading of a couple of volts a.c. depending on the response time of your meter display.

If you get nothing, then work back towards pin 13 of the EZK.

BTW the tach should flicker when you crank as it is connected to pin 13 as well.

I still think that the problem is associated with the tach feed to the digidash. Were you swapping in another dash, or working on the old one ?

Hawkeyes

John,

I was swapping in a newly recovered leather dash and pod, so complete dash, pod, console, trim pieces, etc. were removed.

I'm getting about .5 ac volts when cranking with meter connected between LH pin 1 and a ground. The tach does not flicker, needle does not move.

I got the LH back from Rich yesterday, bolted the LH onto the LH/EZK 'frame', then hooked it up to the connectors. The unit was just lying on the passenger floor, loose. I connected the battery and attempted to start the shark - it started right up, even though I had neglected to reconnect injector 3 that I had used for the Noid light. Engine was running with a dead miss, so I shut it off, reconnected the injector, turned the key and it fired up again, instantly. Ran fine, smooth, no miss, just like before. All the gauges worked, tach, A/C, lights, everything except the turn signals & flasher.

I was elated. The front end was up on jackstands, so I shut the engine off, disconnected the battery, reattached the belly pan & wheels & let it down. I put the console side panels on and gently tucked the EZK/LH frame into the passenger corner, but did not bolt it in. I wanted to do just enough so I could get it out on a test drive.

I reconnected the battery & went to start the car - nothing. It turns over fine, has spark, but will not start, not even fire. I noticed the tach needle does not move when the starter spins. What the hell happened? Tach lead grounding out?

I'm not sure where the tach to LH line is located - not clear to me in the wiring diagram. It must be connected through the flat connection (1 of 4) at rear of digidash.

When does the nightmare end?

Hawkeyes

John Speake

OK, so it was the original dash renovated. No problem.

It sounds as though you have a poor joint in the cable forms that are flexed when you replaced the LH and EZK

Repeat the last set of tests that I suggested with the car in its "no start state". Check everything that moved between start and no start.

Hawkeyes

John,

Thank you once again for your input and suggestions. I am indebted to you.

I did as you suggested, in fact I opened up the insulation so I could visually inspect the wiring itself. There was nothing broken, no open wire or insulation cracked. There was also no power coming from A1 & A2 of the Ignition Circuit Control, as well as nothing from LH to fuel pump and injectors.

Looked like, as you suggested, a problem with signals coming from tach to EZK. I cleaned all the ground points above Central Electric, but still no start.

I then pulled the pod & digidash to try and track down the wiring from rpm sensor & tach to EZK. I took the instrument cluster apart, down to the circuit board & looked for cracks, poor connections, whatever. I re-cleaned the board connections & reconnected the four wire cable plugs to the cluster. I left everything else unconnected & hanging, then turned the ignition...VOILA! It lives!!

I have since driven the car several times, reconnected the EZK & LH 'frame' to the firewall & put everything back together. Only one problem - I now have no turn signals and emergency hazard lights.

The dash indicator light comes on but does not flash. I replaced the relay and all 4 fuses to no avail, and made sure all flasher bulbs were correct & paired. I checked for power at the relay terminals and got nothing.

I believe the flasher is part of the same instrument cluster connecter (#4) as the tach and fuel gauge (fuel gauge also does not work - when I turn off the ignition the gauge moves to 3/4, then back to zero when I turn the key to on). If I slip my hand under the dash & tap the inst. cluster under the fuel gauge, the needle moves from 3/4 to 1/4 & back.

I rechecked the connector & even tightened the 'slip fit' but it made no difference.

I'm going to clean the grounds under the pod & see if that helps.

Is this (fuel gauge, flashers) a common, or often seen problem with the 928?

Thanks,
Hawkeyes

Mrmerlin

to clean the connectors on your dash get a pencil eraser and lightly rub on the metal connection points on the digi dash the 4 big connection points, also check / clean all of the other connections that are bolted to the digidash, also check your connections to the switches IIRC 2 of the connectors can be swapped ( IE will fit other switches) and this could be the answer to the turn lights not working and as always remove battery power while you remove the switches from the pod as the pod is made of sheet aluminum and the switches can/will ground out on the pod and cause a fire if you have power. This problem is related to something you touched, pay close attention to the tach feed we had a similar problem and eventually found that the wire to the EZK to tach was broken

Hawkeyes

[/QUOTE]also check / clean all of the other connections that are bolted to the digidash, also check your connections to the switches IIRC 2 of the connectors can be swapped ( IE will fit other switches) and this could be the answer to the turn lights not working [/QUOTE]

You nailed it! I pulled the pod switches & inspected the blade connections on all. Hazard lights had dual gn/w/bl wires to a female connector, but swtch had no opposing male. Fog light switch was just the opposite. Swapped the switches & EUREKA!!! signal lights work. And here I thought I could take out the pod switches without carefully marking each one - the Porsche engineers are laughing...

Thank you mrmerlin!

As a side note, I've still not figured out why the fuel gauge is so erratic, but I have the solution. I'm going to leave it alone , instead resetting my odometer each time I fill up. Once I get to around 200 miles, it's time to look for the premium pump.

Hawkeyes

marton

glad you found it

about
myself I wait until the fuel low warning light comes on

Marton